Monthly Notifiable Disease Surveillance Report - Mar 2019

Sunday 26th May 2019

Key Notifiable Disease Trends

Enteric Diseases and Acute Gastroenteritis: Enteric infections are the most common notifiable diseases, and several, along with acute gastroenteritis, are increasing in incidence. This increase is partly due to changes in laboratory testing practices, with a shift from culture methods to multiplex PCR (which tests for several diseases at the same time). This means more diseases are likely to be detected and in a more timely manner. For further information, see the 2016 Annual Notifiable Disease Report Commentary.

Pertussis: There were 133 cases (79 confirmed, 47 probable, 2 suspect and 5 under investigation) of pertussis notified in March 2019, compared with 302 cases for the same month in 2018.The number of cases is now back to pre-outbreak levels. For more information, see the latest Pertussis Report.

Measles: There were 49 cases (46 confirmed and 3 under investigation) of measles notified in March 2019, bringing the total for January–March to 70 cases. Cases were reported from Canterbury (34 cases), Waitemata (7 cases), Auckland (7 cases) and Southern (1 case) DHBs. See the outbreak section for more information on measles outbreaks. New Zealand is at ongoing risk of importation from international travellers: The Ministry of Health issued a national advisory about overseas measles outbreaks on 28 February 2019.

OUTBREAKS

Histamine (scombroid) fish poisoning: An outbreak of histamine (scombroid) fish poisoning was reported from Nelson Marlborough DHB in March 2019, involving two probable cases who ate a seafood chowder made with kingfish from a restaurant. There was no leftover food available to test.

Hepatitis A: An outbreak of hepatitis A was reported from Waikato DHB in March 2019, involving nine cases from an early childhood centre. The outbreak is thought to have been ongoing for some time, with the likely index case having travelled to India in April 2018.

Measles: The measles outbreak reported from Canterbury DHB in February continued during March. As at 10 April, 39 confirmed cases had been linked to the outbreak: 36 from Canterbury DHB, two from Southern DHB and one from Waitemata DHB. No source case has been identified. The Canterbury cases were in contact with large numbers of people, including in schools, early childhood centres and healthcare facilities. Genotype B3 has been confirmed in 12 cases and is indistinguishable from a B3 strain detected in the Philippines.

Auckland Regional Public Health reported a family cluster of measles during March, involving eight cases with an unknown source. Genotype B3 was confirmed in three cases and is a different strain to the Canterbury outbreak strain.

The Ministry of Health issued media releases on 13 March and 14 March, encouraging immunisation for people living in Canterbury DHB aged 12 months to 28 years who have never been immunised. ESR has implemented a weekly measles surveillance report at the request of the Ministry of Health.

Influenza: Nine influenza virus outbreaks were reported in March 2019, involving 320 cases. The virus was identified as influenza A in eight outbreaks. The outbreaks were from Capital & Coast (4), Southern (2) Hawke's Bay, MidCentral, and Hutt Valley (1 each) DHBs. Four outbreaks were in institutions (three universities and one orchard accommodation) and five were in long-term care facilities.